HARRISBURG, Pa. - A banner used by a gun-rights group during a protest in Pennsylvania that urged the hanging of a lawmaker has prompted a call for an investigation.

The Philadelphia Inquirer reported Wednesday that Legislative Black Caucus members have asked state police to look into the banner that proclaimed state Rep. Angel Cruz, a Latino Democrat, should be "hung from the tree of liberty for his acts of treason against the Constitution."

The banner was revealed in the state capital of Harrisburg Tuesday as the Philadelphia politician was proposing legislation for additional gun registration regulations.

"I am appalled by the actions by a group of demonstrators," state Rep. Jewell Williams said. "We will not tolerate people making threats against members."

Republican state Rep. Daryl Metcalfe, who organized the gun-rights protest, said he had no knowledge of its controversial message.

"I condemn that language in the strongest terms," the Butler representative told the Inquirer.